Lens-grinding apparatus



C. A. ADAMS LENS GRINDING APPARATUS Filed Dec. :51 2 Sheets-Sheet 1 mma. j 2mm )7, M ATTORNEY.

June 15 1926.

c. A. ADAMS LENS GRINDING APPARATUS Filed Dec. $1, 192:5 zsnuu-suut zINVENTOR.

M ATTORNEY.

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"Gil

Patented June i 15, 1926.

UNITED STATES PATENT OFFICE.

LENS-GRINDING APPARATUS.

Application filed December 31, 1923. Serial No. 688,694.

My invention pertains to lens grinding apparatus, and has for its chiefpurpose to simplify the operation of .producing o tical lenses, andincrease the output thereofi One of the objects of the invention is toform a blocker of increased capacity, togetherwith a special formofmachine with which the same may be used.

Another object thereof is to produce a blocker of a hollow formation,from which the air may be exhausted, and provided on its outer surfacewith spots to receive the lenses, which spots are in communication withthe interior of the blocker, so that the lenses can be caused to adherethereto by the vacuum in the interior of the blocker.

The above named, and other features and advantages of the invention,will more full appear from the following specificatlon, re 1 erencebeing had to the accompanying drawings, in which: 1

Fig. 1 is a side elevation of a machine forming a part of the invention.

Fig. 2 is a vertical section thereof, with a blocker in place therein.

Fig. 3 is a plan view thereof. Fig. 4 is a view similar to Fig; 1,showing a modified use of the machine.

Fig. 5 is a side elevation of a modified form of blocker.

Fig. 6 is a view of a spherical blocker of a similar formation as theone shown in Fig. 5.

Fig. 7 is a section.

Fig. 8 is a similar view of the vent 47.

Referring first to the first three figures of the drawings, thereference number 1 indicates a pairof uprights, to the-sides of whichdetail of the air-valve 45, in

is attached a pair of brackets 2 and 3, the

first of which is mounted at a distance above the other. Supported bythe bracket 2 are twin bearings 4 and 5, spaced apart to provide roomfor a worm-gear wheel 6, in mesh with a worm 7 on a shaft 8, rotatablymountedin a pair of arms 9 secured to the bracket 2. The shaft 8 andworm thereon are accommodated in an opening 10 in the bracket, and powermay be applied to said shaft to impart rotation to the worm 7 and gearwheel 6. Under some manufacturing conditions the shaft 8 would comprisea line shaft, with a number of the machines connected therewith. Thegear-wheel 6 is held in position by means of a vertical shaft 11,rotatable with the wheel, but vertically formed in its surface, adaptedto movable with relation thereto by means of a rib and channel formationshown at 12.

On the lower end of the shaft 11 is a disk 13, to which is attached abowl-shaped member 14, commonly called a tool, by means of a set-screw15. In the rotary movement of the shaft 11 the tool 14 is caused torevolve therewith.

The bracket 3 supports a pair'of bearings 16 and 17, spaced apart toprovide roomfor a worm-gear wheel 18, in mesh with a worm drive 19,fixed on a shaft 20, journaled in the ends of arms 21, attached to thebracket 3.} A space 22 is provided in said bracket for the shaft andworm drive thereon, and said shaft also is designed to have powerapphedthereto, to'cause a rotation thereof in a direction opposite tothe rotation of the shaft. 8. The wheel 18 is fixed to a vertical shaft23, rotatable in the bearings 16 and17, and at the upper end of theshaft 23 is a disk 24, to which is fixed a tool 25, by means ofasst-screw 26. The tools 14 and 25 are hollowed .out, formingsemi-spherical res cesses 27 and 27, the edges of which are flaredoutwardly at the rims of the'tools.

' In Fig. 2 the machine is shown with a spherical blocker. 28 containedin the tools 14 and 25, said blocker having spots 29 "'01 lenses, asshown at 30. These spots are formed in the manner set forth in acompanion application filed in theUnited States Patent Oflice byapplicant 'onthe 26th dayof De-v cember, 1923, Serial No. 682,693, andas set forth therein, the lenses are heldin position in the spots'by athin layer of pitch or similar adhesive. The diameter of the blockercorresponds with that of the recesses in the tools 14 and 25, and whenthe lenses are perfectly ground the outer faces thereof conform to thecurvature of the blocker, so that the blockerand lenses thereon willconform to the inner shapes of the recesses 27 and 27. The lower tool isprovided with a quantity of abrasive material in the usual manner,and-by reason of the tools 14 and 25 being rotated in oppositedirections the position of the blocker'28 is constantly chan ingtherein, so that all of the lenses are su mitted to the grindingoperation. As the work proceeds the tool 14 is moved gradually downwardlby force of gravity, until the blocker is fina 1y contained within therecesses in the tools, with its face in contact with the walls thereof.When I the lenses positioned thereon, it is in contact tion.

with the flaring faces of said recesses, as shownin Fig. 2.

A special advantage is gained by the use of the spherical blocker, whichhas been impossible heretofore on account of the manner of preparing theblocker for operation, which consisted in providing its surface with alayer of pitch, with spots formedthereon. With this method it was onlyossible to make use of a semi-spherical bloc er, with a limited numberof spots thereon, a portion of the blocker near the edge thereof beingblank, for waste space. By the use of the spherical blocker it is notonly possible to double the number of spots which are found on asemi-spherical blocker, but an additional row of spots can be providedalong the line of the greatest diameter of the sphere. This increasesthe capacity of the blocker by approximately fifty per cent. Thegrinding operation is also speeded up to a considerable'extent by theuse of the two tools 14 and 25, operating in opposite directions.

The shaft 11 is shown provided with a central channel 11, which iscontinued downwardly through the tool 14, through which water may beintroduced to the center of the tools during the grinding operation, tokeep the abrasive material in a desired moist condition, and to preventthe parts from becoming overheated from the friction-resulting from thegrinding opera- In Fig. 4 the tool'14 is replaced by a crank member 31,carrying a pin 32, eccentrically positioned, for engagement with theshank 33 of a blocker 34. This blocker is of the shape of those now inuse, but is ofa hollow formation, the flat side thereof being closed bya plate 35. In the curved surface of the blocker are spots 36. outtherein in the manner hereinbefore set forth, and provided with centralopenings 37, communicating with the space within the blocker. Byproviding the spots'with a plurality of lenses, and exhausting the'airfromjthe block, the suction on the inner faces of the lenses will causethem to adhere tightly to the spots,

enabling them to pass through the grinding operation. Air may beexhausted from the blocker through a tube 38, containing a check-valve,(not shown) which prevents the I water, to cause them to adhere slightlyuntil the air is exhausted from the blocker. This may be done by an airpump or simi lar machine. The blocker is then placed in .the tool 25 androtated in the usual manner. After the lenses have been suflicientlyground and polished, they can be released from the blocker by admittingair to the interior thereof through an opening in the plate 35 normallyclosed by a thumb-screw In Fig. 6 is shown a blocker 41 of sphericalform, for use in the machine hereinbefore first described, butconstructed after the manner of the blocker 34, the sphere being hollow,and having spots 42, with central openings 43 communicating with theinterior. The lenses are positioned on the spots 36 the same as in theblocker 34, and the air exhausted from .theblocker. This can be donethrough an opening 44 in one side of the blocker, fitted with a tube 45,provided with a check-valve preventing return of air inwardly throughthe tube. The outer end of the tube projects into the opening 44,v forsuitable connection with an airpump, and said projection is normallyclosed by a cap 46, which is within the curve of the blocker. Afterbeing provided with a plurality of lenses the blocker 41 is placed inthe machine, in the same manner as with the blocker 30," and the lensesreduced to the desired convexity. The air suction can be released bymeans of an opening 47 in the shell of the blocker, fitted with a screw48, seated on a gasket 49,- the head of the screw being below thesurface of the blocker. Upon the air being returned to the blocker, thelenses can be removed therefrom. The spots 42 are provided with gaskets50, to prevent the passage of air between the lenses and faces of thespots.

Upon occasion the shaft 11 can be held in an elevated position by meansof a handscrew 51 in the bearing 4.

What I claim,and desire to secure by Letters Patent, is:

1. In a device -of the class described, a pair of lens g'ri'nding tools,mounted to operate in opposition, in opposite directions; andprovided-with semi-spherical recesses; and a spherical blocker providedon its face with lens retaining spots. of a diameter corresponding withthat of said recesses.

2. In a device of the class described, a spherical blocker having aplurality of lens spotting depressions formed on its surface. a 3. In adevice of the class described, a. spherical blocker having a pluralityof lens spotting depressions formed on its surface and means for seatingand securing lens] blanks within such depressions. I 4. In a device ofthe class described. a" pair of lens grinding tools mounted to open atein opposite directions and provided with semi-spherical depressions, anda s herical blocker provided on its face with ens retaining depressions.

5. A device of the character described comprising a pair of opposed lensgrinding tools having recesses formed therein, a blocker adapted to havea plurality of lenses mounted thereon, said blocker adapted to bereceived in the recesses of the opposed tools, and means for rotatingthe tools in opposite directions, the rotation of the tools causing theblocker to be rotated within the recesses relative to the tools to bringthe lenses carried thereby into engagement with different portions orsurfaces of the tools.

6. A device of the characted described comprising apair of opposed lensgrinding .tools having recesses formed therein, a

blocker having lens receiving spots formed around its surface, saidblocker adapted to be received in the recesses of the opposed tools,means for securing'the lenses in the spots in the blocker, and means forrotating the tools in opposite directions, the rotation of the toolscausing the blocker to be zotated within the recesses relative to the,ools.

In testimony whereof I'aflix my signature,

CHARLES A. ADAMS.

